The present invention relates generally to a radiant-type heater and more particularly to a radiant-type kerosene flare heater or, in other words, primarily to a radiant-type kerosene heater for warming a room by forwardly radiating heat from a heating element heated by a burner in an exterior case.
Furthermore, the present invention provides a novel radiant-type kerosene flare heater which uses a rotary atomization type burner, a burner head having a unique horseshoe-shaped flame port to minimize carbon monoxide concentration and a heating element suspended inside a burner tube. The invention minimizes thermal capacity so as to reduce carbon monoxide concentration while maintaining radiation efficiency. It has a simple construction which makes it durable and aesthetically pleasing.
A variety of portable heaters have been employed in the home. Recently, radiant-type heaters which provide comfort and low noise have been considered as replacements for warm air blowing heaters, as disclosed in, for example, U.S. Pat. No. 4,488,536, which can easily maintain a uniform room temperature. This tendency is particularly remarkable in a cold area. The present invention provides a novel radiant-type kerosene flare heater which reveals the beauty of the flame. This feature has been neglected in the past but stresses a visual warmness which can be provided by a heating element having a simple structure.
A heater having a heating element which is heated by the flame of a burner is disclosed, for example, in Japanese Utility Model Publication No. 61-24819/1986. This red heat member comprises a cylindrically shaped metallic sheet such as a high chromium stainless steel and has a large number of through-holes bored therethrough in order to increase the degree of heating when the heating element is heated by the burner flame.
The conventional heating element described above is produced by rolling a metallic sheet into a cylindrical form, overlapping its end portions and connecting them together by spot-welding or a like method. The heating element thus produced is put onto the burner. When this heating element is subjected to the repetition of heating and cooling in the course of use of the heater, it cannot absorb the stress due to thermal expansion and thermal deformations such as local recesses, occur on a peripheral wall. Though this thermal deformation can be prevented by use of a thick metallic sheet, the thermal capacity of the heating element increases and the degree of heating drops if the thicker metallic sheet is used.
A combustion apparatus, for temporarily pre-mixing a gaseous fuel and primary air inside a burner body and jetting this fuel-air pre-mixture from a flame port of the burner head, is disclosed in Japanese Utility Model Publication Nos. 60-2415/1985 and 60-2420/1985. However, the former reference involves the drawbacks in that the structure of the burner body is complex because a secondary air pipe must be inserted through the burner body and such fitting of the secondary air pipe is time-consuming. The latter prior art publication also has the problem that the construction of the burner head is extremely complex because a secondary air passage must be formed in the burner head itself.
A heater equipped with a reflection plate which warms the room primarily by the radiant heat from a heat generation portion is disclosed, for example, in Japanese Patent Publication (unexamined) No. 54-85538/1979. According to this publication, both radiation heating and warm air blowing can be accomplished by providing a heat generation portion inside a main body case having an opening on its front surface, and also providing a blower between a reflection plate and the main body case. A heat shielding plate is disposed above the heat generation portion in order to prevent an upper tray of the main body case from being heated directly by the heat of the heat generation portion. However, when the heat generation portion produces high temperatures, the heated air stays in the space between the heat shielding plate and the upper tray and the temperature of the upper tray rises beyond a desirable level, thus causing various problems.
Combustion of a pre-mixture of fuel and air has been employed widely in kerosene heaters for home use because complete combustion can be obtained easily, the combustion flame is stable and a wide range of combustion is attained. In general, in combustion of such a pre-mixture, the kerosene is atomized and then vaporized by a heating surface and after being forcibly mixed with the primary air, is burnt by the burner head. Such pre-mixture combustion is classified into three type of systems: jet systems, rotary atomization systems and vaporization systems.
The rotary atomization system employed in the present invention has great advantages in that the kerosene fuel particles are very small and can be vaporized easily, the amount of the remaining fuel on the vaporization surface is small, even for a fuel having a high boiling point or for discolored kerosene, because the entire vaporization surface can be utilized by rotary atomization, the flame formation is stable and complete combustion can be obtained because the most desirable mixture of fuel and air is attained.